Analgesics, Opioid

Definition

Opioid analgesics, also known as narcotic analgesics, are pain relievers that act on the central nervous system. Like all narcotics, they may become habit-forming if used over long periods.

Purpose

Opioid analgesics are used to relieve pain from a variety of conditions. Some are used before or during surgery (including dental surgery) both to relieve pain and to make anesthetics work more effectively. They may also be used for the same purposes during labor and delivery.

Opioids are also given to relieve the pain of terminal cancer, diabetic neuropathy, lower back pain, and other chronic diseases or disorders. The World Health Organization (WHO) has established a three-stage "ladder" for the use of opioids in managing cancer pain.

Description

Opioid analgesics relieve pain by acting directly on the central nervous system. However, this can also lead to unwanted side effects, such as drowsiness, dizziness, breathing problems, and physical or mental dependence.

Among the drugs in this category are codeine, propoxyphene (Darvon), propoxyphene and acetaminophen (Darvocet N), meperidine (Demerol), hydromorphone (Dilaudid), morphine, oxycodone, oxycodone and acetaminophen (Percocet, Roxicet), and hydrocodone and acetaminophen (Lortab, Anexsia). These drugs come in many forms—tablets, syrups, suppositories, and injections, and are sold only by prescription. For some, a new prescription is required for each new supply—refills are prohibited according to federal regulations.

Recommended dosage

Recommended doses vary, depending on the type of opioid analgesic and the form in which it is being used. Doses may be different for different patients. Check with the physician who prescribed the drug or the pharmacist who filled the prescription for correct dosages, and make sure to understand how to take the drug.

Always take opioid analgesics exactly as directed. Never take larger or more frequent doses, and do not take the drug for longer than directed. Do not stop taking the drug suddenly without checking with the physician or dentist who prescribed it. Gradually tapering the dose may the chance of withdrawal symptoms.

Precautions

Anyone who uses opioid analgesics—or any narcotic—over a long time may become physically or mentally dependent on the drug. Physical dependence may lead to withdrawal symptoms when the person stops taking the medicine. Building tolerance to these drugs is also possible when they are used for a long period. Over time, the body needs larger and larger doses to relieve pain.

Take these drugs exactly as directed. Never take more than the recommended dose, and do not take the drugs more often than directed. If the drugs do not seem to be working, consult your physician. Do not share these or any other prescription drugs with others because the drug may have a completely different effect on the person for whom it was not prescribed.

Children and older people are especially sensitive to opioid analgesics and may have serious breathing problems after taking them. Children may also become unusually restless or agitated when given these drugs.

Opioid analgesics increase the effects of alcohol. Anyone taking these drugs should not drink alcoholic beverages.

Some of these drugs may also contain aspirin, caffeine, or acetaminophen. Refer to the entries on each of these drugs for additional precautions.

Special conditions

People with certain medical conditions or who are taking certain other medicines can have problems if they take opioid analgesics. Before taking these drugs, be sure to let the physician know about any of these conditions.

ALLERGIES. Let the physician know about any allergies to foods, dyes, preservatives, or other substances and about any previous reactions to opioid analgesics.

PREGNANCY. Women who are pregnant or plan to become pregnant while taking opioid analgesics should let their physicians know. No evidence exists that these drugs cause birth defects in people, but some do cause birth defects and other problems when given to pregnant animals in experiments. Babies can become dependent on opioid analgesics if their mothers use too much during pregnancy. This can cause the baby to go through withdrawal symptoms after birth. If taken just before delivery, some opioid analgesics may cause serious breathing problems in the newborn.

BREAST FEEDING. Some opioid analgesics can pass into breast milk. Women who are breast feeding should check with their physicians about the safety of taking these drugs.

KEY TERMS

Analgesic— Medicine used to relieve pain.

Central nervous system— The brain and spinal cord.

Colitis— Inflammation of the colon (large bowel)

Hallucination— A false or distorted perception of objects, sounds, or events that seems real. Hallucinations usually result from drugs or mental disorders.

Inflammation— Pain, redness, swelling, and heat that usually develop in response to injury or illness.

Narcotic— A drug derived from opium or compounds similar to opium. Such drugs are potent pain relievers and can affect mood and behavior. Long-term use of narcotics can lead to dependence and tolerance.

Tolerance— A decrease in sensitivity to a drug. When tolerance occurs, a person must take more and more of the drug to get the same effect.

Withdrawal symptoms— A group of physical or mental symptoms that may occur when a person suddenly stops using a drug to which he or she has become dependent.

OTHER MEDICAL CONDITIONS. These conditions may influence the effects of opioid analgesics:

• head injury. The effects of some opioid analgesics may be stronger and may interfere with recovery in people with head injuries.
• history of convulsions. Some of these drugs may trigger convulsions.
• asthma, emphysema, or any chronic lung disease

• heart disease
• kidney disease
• liver disease
• HIV infection. Patients undergoing highly active antiretroviral therapy, or HAART, are at increased risk for adverse effects from opioid analgesics.
• underactive thyroid. The chance of side effects may be greater.
• Addison's disease (a disease of the adrenal glands)
• colitis
• gallbladder disease or gallstones. Side effects can be dangerous in people with these conditions.
• enlarged prostate or other urinary problems
• current or past alcohol abuse
• current or past drug abuse, especially narcotic abuse
• current or past emotional problems. The chance of side effects may be greater.

USE OF CERTAIN MEDICINES. Taking opioid narcotics with certain other drugs may increase the chances of serious side effects.

Side effects

Some people experience drowsiness, dizziness, lightheadedness, or a false sense of well-being after taking opioid analgesics. Anyone who takes these drugs should not drive, use machines, or do anything else that might be dangerous until they know how the drug affects them. Nausea and vomiting are common side effects, especially when first beginning to take the medicine. If these symptoms do not go away after the first few doses, check with the physician or dentist who prescribed the medicine.

Dry mouth is another common side effect. Dry mouth can be relieved by sucking on sugarless hard candy or ice chips or by chewing sugarless gum. Saliva substitutes, which come in liquid or tablet forms, also may help. Patients who must use opioid analgesics over long periods and who have dry mouth should see their dentists, as the problem can lead to tooth decay and other dental problems.

The following side effects are less common. They usually do not need medical attention and will go away after the first few doses. If they continue or interfere with normal activity, check with the physician who prescribed the medicine.

• headache
• loss of appetite
• restlessness or nervousness
• nightmares, unusual dreams, or problems sleeping
• weakness or tiredness
• mental sluggishness
• stomach pain or cramps
• blurred or double vision or other vision problems
• problems urinating, such as pain, difficulty urinating, frequent urge to urinate, or decreased amount of urine
• constipation.

Other side effects may be more serious and may require quick medical attention. These symptoms could be signs of an overdose. Get emergency medical care immediately.

• cold, clammy skin
• bluish discoloration of the skin
• extremely small pupils
• serious difficulty breathing or extremely slow breathing
• extreme sleepiness or unresponsiveness
• severe weakness
• confusion
• severe dizziness
• severe drowsiness
• slow heartbeat
• low blood pressure
• severe nervousness or restlessness

In addition, these less common side effects do not require emergency medical care, but should have medical attention as soon as possible:

• hallucinations or a sense of unreality
• depression or other mood changes
• ringing or buzzing in the ears
• pounding or unusually fast heartbeat
• itching, hives, or rash
• facial swelling
• trembling or twitching
• dark urine, pale stools, or yellow eyes or skin (after taking propoxyphene)
• increased sweating, red or flushed face (more common after taking hydrocodone and meperidine)

Interactions

Anyone taking these drugs should notify his or her physician before taking opioid analgesics:

• Central nervous system (CNS) depressants, such as antihistamines and other medicines for allergies, hay fever, or colds; tranquilizers; some other prescription pain relievers; seizure medicines; muscle relaxants; sleeping pills; some anesthetics (including dental anesthetics).
• Monoamine oxidase (MAO) inhibitors, such as phenelzine (Nardil) and tranylcypromine (Parnate). The combination of the opioid analgesic meperidine (Demerol) and MAO inhibitors is especially dangerous.
• Tricyclic antidepressants, such as amitriptyline (Elavil).
• Anti-seizure medicines, such as carbamazepine (Tegretol). May lead to serious side effects, including coma, when combined with propoxyphene and acetaminophen (Darvocet-N) or propoxyphene (Darvon).
• Muscle relaxants, such as cyclobenzaprine (Flexeril).
• Sleeping pills, such as triazolam (Halcion).
• Blood-thinning drugs, such as warfarin (Coumadin).
• Naltrexone (Trexan, Revia). Cancels the effects of opioid analgesics.
• Rifampin (Rifadin).
• Zidovudine (AZT, Retrovir). Serious side effects when combined with morphine.

Opioids may also interact with certain herbal preparations sold as dietary supplements. Among the herbs known to interact with opioids are valerian (Valeriana officinalis ), ginseng (Panax ginseng ), kava kava (Piper methysticum ), and chamomile (Matricaria chamomilla ). As of early 2004 the National Center for Complementary and Alternative Medicine (NCCAM) is beginning a study of the possible interactions between St. John's wort (Hypericum perforatum, a herb frequently used to relieve symptoms of depression, and the opioid analgesics fentanyl and oxycodone. It is just as important for patients to inform their doctor of herbal remedies that they take on a regular basis as it is to give the doctor a list of their other prescription medications.

Resources

BOOKS

Beers, Mark H., MD, and Robert Berkow, MD., editors. "Pain." Section 14, Chapter 167 In The Merck Manual of Diagnosis and Therapy. Whitehouse Station, NJ: Merck Research Laboratories, 2002.

Pelletier, Dr. Kenneth R. The Best Alternative Medicine, Part I: Western Herbal Medicine. New York: Simon and Schuster, 2002.

Wilson, Billie Ann, RN, PhD, Carolyn L. Stang, PharmD, and Margaret T. Shannon, RN, PhD. Nurses Drug Guide 2000. Stamford, CT: Appleton and Lange, 1999.

PERIODICALS

Campbell, D. C. "Parenteral Opioids for Labor Analgesia." Clinical Obstetrics and Gynecology 46 (September 2003): 616-622.

Compton, P., and P. Athanasos. "Chronic Pain, Substance Abuse and Addiction." Nursing Clinics of North America 38 (September 2003): 525-537.

Faragon, J. J., and P. J. Piliero. "Drug Interactions Associated with HAART: Focus on Treatments for Addiction and Recreational Drugs." AIDS Reader 13 (September 2003): 433-450.

Markowitz, J. S., J. L. Donovan, C. L. DeVane, et al. "Effect of St John's Wort on Drug Metabolism by Induction of Cytochrome P450 3A4 Enzyme." Journal of the American Medical Association 290 (September 17, 2003): 1500-1504.

Soares, L. G., M. Marins, and R. Uchoa. "Intravenous Fentanyl for Cancer Pain: A 'Fast Titration' Protocol for the Emergency Room." Journal of Pain and Symptom Management 26 (September 2003): 876-881.

Watson, C. P., D. Moulin, J. Watt-Watson, et al. "Controlled-Release Oxycodone Relieves Neuropathic Pain: A Randomized Controlled Trial in Painful Diabetic Neuropathy." Pain 105 (September 2003): 71-78.

ORGANIZATIONS

National Center for Complementary and Alternative Medicine (NCCAM) Clearinghouse. P.O. Box 7923, Gaithersburg, MD 20898-7923. (888) 644-6226. 〈http://nccam.nih.gov〉.

U. S. Food and Drug Administration (FDA). 5600 Fishers Lane, Rockville, MD 20857. (888) 463-6332. 〈http://www.fda.gov〉.

Opioids

Definition

Opioids are narcotic drugs that are generally prescribed to manage pain. The most commonly prescribed opioids are: buprenorphine, butorphanol, codeine, fentanyl, hydrocodone, hydromorphone, levorphanol, meperidine , methadone, morphine, nalbuphine, oxycodone, oxymorphone, pentazocine, and propoxyphene. These opioids are prescribed alone or in combination with aspirin or acetaminophen (Tylenol).

The most common brand names for these drugs are:

• Actiq
• Astramorph PF
• Buprenex
• Cotanal-65
• Darvon
• Demerol
• Dilaudid
• Dolophine
• Duragesic
• Duramorph
• Hydrostat IR
• Kadian
• Levo-Dromoran
• Methadose
• M S Contin
• MSIR
• MS/L
• MS/S
• Nubain
• Numorphan
• OMS
• Oramorph SR
• OxyContin
• PP-Cap
• Rescudose
• RMS Uniserts
• Roxanol
• Roxicodone
• Stadol
• Talwin

When combined with aspirin or acetaminophen, the most common brand names are:

• Allay
• Anexsia
• Anolor
• Bancap-HC
• Capital with Codeine
• Co-Gesic
• Damason-P
• Darvocet
• Darvon
• DHCplus
• Dolacet
• Dolagesic
• Duocet
• E-Lor
• Empirin with codeine
• Endocet
• Endodan
• EZ III
• Hycomed
• Hyco-Pap
• Hydrocet
• Hydrogesic
• HY-PHEN
• Lorcet
• Lortab
• Margesic
• Oncet
• Panacet
• Panasal
• Panlor
• Percocet
• Percodan
• Phenaphen with codeine
• Polygesic
• Propacet
• Propoxyphene Compound-65
• Pyregesic-C
• Roxicet
• Roxilox
• Roxiprin
• Stagesic
• Synalgos-DC
• Talacen
• Talwin compound
• T-Gesic
• Tylenol with codeine
• Tylox
• Ugesic
• Vanacet
• Vendone
• Vicodin
• Vicoprofen
• Wygesic
• Zydone

Purpose

Opioids are primarily used to manage pain. Some narcotics are also used just prior to, or during, surgery to increase the effectiveness of certain anesthetics. Codeine and hydrocodone are used to relieve coughing. Methadone is used to help people control their dependence on heroine or other narcotics.

Description

Opioids act on the central nervous system (CNS)to relieve pain. Many of these drugs are habit-forming and physical dependence may lead to withdrawal side effects when the medication is stopped. Because of the potential habit-forming nature of these drugs, most prescriptions cannot be refilled and a new prescription must be obtained after each preceding prescription runs out.

Recommended dosage

Opioids may be taken either orally (in pill or liquid form), by injection (or as part of an intravenous [IV]. line), as an anal suppository, or as a patch attached to the skin. The dosage prescribed may vary widely depending on the patient, the cancer being treated, and whether or not other medications are also being taken.

A typical adult dosage for buprenorphine is 0.3 mg injected into a muscle or vein every six hours as necessary. For children between the ages of two and twelve years, the dosage is typically 0.002 to 0.006 mg per kilogram (2.2 pounds) of body weight.

A typical adult dosage for butorphanol is 1-4 mg injected into a muscle or 0.5-2 mg injected into a vein every four hours as necessary. For children between the ages of two and twelve years, the dosage is typically based on the body weight of the child.

A typical adult dosage for codeine is 15-60 mg taken orally or injected into a muscle or vein every four to six hours as necessary for pain. This dosage is decreased to 10 to 20 mg when codeine is used to control coughing.

Fentanyl is most often used to manage pain in cancer patients who are already receiving and are tolerant to other opioids. This drug is available as a lozenge and as a skin patch. It is not used for the treatment of pain caused by injury or surgery. The dosage of fentanyl is determined on an individual patient basis by that patient's oncologist.

A typical adult dosage for hydrocodone is 5-10 mg taken orally every four to six hours as necessary for pain, 5 mg to control coughing.

A typical adult dosage for hydromorphone is 1-2 mg injected into a muscle, 2-2.5 mg taken orally, or 3 mg taken as a suppository every three to six hours as necessary.

A typical adult dosage for levorphanol is 2-4 mg taken orally or injected into a vein every four hours as necessary.

A typical adult dosage for meperidine is 100 mg taken orally or injected into a muscle or vein every four hours as necessary.

A typical adult dosage for methadone is 5-20 mg as an oral solution, 2.5-10 mg as an oral tablet or injection, every four to eight hours as necessary for pain. When used for detoxification, methadone is initially given in a dose of 15-40 mg per day as an oral solution. This dose is then decreased until the patient no longer requires the medication. The injection form of methadone is only used for detoxification in patients who are unable to take the medication by mouth.

Morphine is most often used to manage severe, chronic pain in patients who have already been receiving other narcotic pain relievers. The starting dose of morphine is generally determined based on the dosages of prior narcotic pain relievers the patient had been receiving. A typical starting dose is 5-30 mg every four hours.

A typical adult dosage for nalbuphine is 10 mg injected into a muscle or vein every three to six hours as necessary.

A typical adult dosage for oxycodone is 5 mg taken orally every three to six hours, or 10-40 mg taken as a suppository three to four times per day as necessary.

A typical adult dosage for oxymorphone is 1-1.5 mg injected into a muscle every three to six hours, or 5 mg taken as a suppository every four to six hours as necessary.

A typical adult dosage for pentazocine is 50 mg taken orally, or 30 mg injected into a muscle or vein every three to four hours as necessary.

Propoxyphene comes in two salt forms: propoxyphene hydrochloride and propoxyphene napsylate. The typical adult dosage for propoxyphene hydrochloride is 65 mg taken orally every four hours with a maximum daily dosage of 390 mg. The typical adult dosage for propoxyphene napsylate is 100 mg taken orally every four hours with a maximum daily dosage of 600 mg.

Precautions

Opioids magnify the effects of alcohol and other central nervous system depressants, such as antihistamines, cold medicines, sedatives, tranquilizers, other prescription and over-the-counter pain medications, barbiturates, seizure medications, muscle relaxants, and certain anesthetics including some dental anesthetics. Alcohol and other central nervous system depressants should not be taken or consumed while opioids are being taken.

Opioids are powerful narcotics. These drugs can cause some people to feel drowsy, dizzy, or lightheaded. People taking opioids should not drive a car or operate machinery.

Opioids can be habit-forming. Patients who have been taking these types of medication for a period of several weeks should not stop taking this type of medication all at once. The dosage should be slowly tapered off to avoid potential withdrawal side effects.

Intentional or accidental overdose of any of the opioids can lead to unconsciousness, coma, or death. The signs of opioid overdose include confusion, difficulty speaking, seizures, severe nervousness or restlessness, severe dizziness, severe drowsiness, and/or slow or troubled breathing. These symptoms are increased by alcohol or other central nervous system depressants. Anyone who feels that he or she, or someone else, may have overdosed on opioids, or a combination of opioids and other central nervous system depressants, should seek emergency medical attention for that person at once.

Opioids can interfere with or exacerbate certain medical conditions. For these reasons, it is important that the prescribing physician is aware of any current case, or history of:

• alcohol abuse
• brain disease or head injury
• colitis
• drug dependency, particularly of narcotics
• emotional problems;
• emphysema, asthma, or other chronic lung disease
• enlarged prostate
• gallstones or gallbladder disease
• heart disease
• kidney disease
• liver disease
• problems with urination
• seizures
• underactive thyroid

Side effects

The most common side effects of opioids include:

• constipation
• dizziness
• drowsiness
• itching
• nausea
• urine retention
• vomiting

Less common side effects of opioids include:

• abnormally fast or slow heartbeat
• blurred or double vision
• cold, clammy skin
• depression or other mood changes
• dry mouth
• fainting
• hallucinations
• hives
• loss of appetite (anorexia )
• nightmares or unusual dreams
• pinpoint pupils of the eyes
• redness or flushing of the face
• restlessness
• rigid muscles
• ringing or buzzing in the ears
• seizure
• severe drowsiness
• skin reaction at the site of injection
• stomach cramps or pain
• sweating
• trouble sleeping (insomnia)
• yellowing of the skin or whites of the eyes

Interactions

Opioids should not be taken in combination with any prescription drug, over-the-counter drug, or herbal remedy without prior consultation with a physician. It is particularly important that the prescribing physician be aware of the use of any of the following drugs:

• carbamazepine (Tegretol; antiepileptic)
• central nervous system depressants
• monoamine oxidase (MAO) inhibitors (a class of anti-depressants) such as furazolidone, isocarboxazid, pargyline, phenelzine, procarbazine , or tranylcypromine
• Naltrexone (opioid antagonist)
• Rifampin (antituberculosis drug)
• tricyclic antidepressants such as amitriptyline , amoxapine, clomipramine, desipramine, doxepin, imipramine, nortiptyline, protriptyline, or trimipramine
• Zidovudine (antiviral against aids virus)
• any radiation therapy or chemotherapy medicines

Paul A. Johnson, Ed.M.

KEY TERMS

Central nervous system depressant

—Any drug that tends to reduce the activity of the central nervous system. The major drug categories included in this classification are alcohol, anesthetics, antianxiety medications, antihistamines, antipsychotics, hypnotics, narcotics, sedatives, and tranquilizers.

Narcotic

—Any drug that produces insensibility or stupor and/or generally causes effects similar to those caused by morphine.